Virtualization in information processing systems allows for multiple instances of one or more operating systems to run on resources (or components) of one or more hosting computing devices (“host”). Virtualization is typically implemented by using software (e.g., a virtual machine monitor, or a “VMM”) to present to each OS a “virtual machine” (“VM”) having virtualized hardware resources, including one or more virtual processors, that the OS may completely and directly control, while the VMM maintains a system environment for implementing virtualization policies such as sharing and/or allocating the physical resources among the VMs (the “virtualization environment”). Each OS, and any other software, that runs on a VM is referred to as a “guest” or as “guest software,” while “host software” is software, such as a VMM, that runs outside of, and may or may not be aware of, the virtualization environment.
VM(s) may run on one or more hosts. Further, each of the VM(s) may run under the control of a respective OS which may or may not be different from the OS of another VM. Hardware resources of the one or more hosts may also be virtualized. Thus, instead of directly interacting with physical hardware devices (such as processing units, hard drives, network interfaces (NICs) etc.), the operating systems of VM(s) may control virtualized hardware components (such as virtual processing units, virtual disks, and virtual network interface cards etc.). The virtualization of hardware devices may hide the physical characteristics of the one or more hosts from users.